There is converging evidence that environmental cues related to tobacco use are critically involved in tobacco dependence. Dr. Caggiula's laboratory is currently investigating the impact of environmental cues on nicotine (NIC) self-administration (SA) in rats. They have found that NIC enhances responding for other reinforcers (i.e., delivery of an environmental cue). However, one shortcoming of these studies is that delivery of the cue and delivery of NIC depend on the same behavior (i.e., pressing an "active" lever). Thus, the nature of the interaction between the reinforcers (NIC and cue) is not completely clear. The experiments outlined in the present proposal will begin to examine the nature of the interaction between NIC and the environmental cue using a "two-lever" paradigm. That is, NIC infusions and cue presentations will be controlled by two distinct operants (i.e., pressing different levers). This technique will provide a more sensitive assay of how NIC reinforces behavior and will expand our understanding of chronic tobacco use. Increasing the sensitivity of NIC SA models will provide useful and readily applicable information for behavioral and pharmacological tobacco cessation programs.